Automatic circuit reclosers (ACR), or reclosers, are protective devices located in electrical substations and transmission circuits that respond to defined abnormal operating conditions caused by overcurrents, or faults. Reclosers trip open in programmed response to faults to limit the duration of the faults and corresponding exposure to dangerously high voltages and arcing, both of which may cause personnel injury and property and environmental damage. Reclosers use microprocessor controls to provide fault sensing and corrective logic that remove the source of electrical energy flowing to the fault by causing the recloser to open or trip.
A conventional recloser is powered by electrical energy from a low voltage power source that receives power from the electrical substation or transmission circuit being protected. An electrical battery is provided as a secondary source of power for the microprocessor control in the event that the power source fails. The battery is charged by the power source, and is subject to aging effects and eventual failure. When the recloser has a low or marginal quality battery, and when the power source fails, the control stops functioning after the battery supply voltage falls below a certain minimum value. In such a case, the control does not provide any logic to trip or open the recloser should a fault occur, which may result in the potentially damaging and injurious fault persisting for the time necessary for a backup device to operate and remove the source of electrical power for the fault.
Typically, utility personnel manually test the condition of the battery before applying a hot line or a non-reclosing tag and commencing hot line work. The results of the test are manually interpreted to determine whether the hot line work may proceed in a safe manner, and the interpretation of the results may vary among utility companies and among crews within the utility companies. Once testing is complete, the personnel may move away from the recloser to perform the hot line work. As such, the personnel may not be in a position to observe the loss of power to the recloser and/or the failure of the battery, and to respond by stopping the hot line work. In addition, the personnel may be in a location at which they may not receive radio communications indicating that power has been lost and/or the battery has failed.